According to the lawsuit's 474 plaintiffs, BP's refinery released sulfur dioxide, methyl carpaptan, dimethyl disulfide and other toxic chemicals for 15 consecutive days in November 2011, inflicting permanent damage to the environment and endangering the health of residents.

The plaintiffs claim BP was aware of the chemical releases before it sold the refinery for $2.4 billion on Feb. 1.

"BP made a tremendous amount of money while doing business in Texas City, sold the refinery at a large profit and then left Texas City and the people of Galveston County holding the bag for its mess," the complaint says.